Georgia congressman John Lewis deployed a strategy from his days as a civil rights activist and the viral nature of social media to stage a dramatic sit-in Wednesday on the House floor with his fellow Democrats to force a vote on gun control.

Leading U.S. Senate Democrats are discussing how to revive a push for legislation imposing additional gun controls in the wake of last weekend's mass shooting in Florida, according to a senior Senate Democratic aide on Monday. The aide did not provide details and senators, who have been on a weekend recess, will be back on Tuesday.

As Republicans and Democrats gird for a showdown over when and with whom to replace the late Supreme Court Justice Antonin Scalia, the political question is which party will benefit from the battle. If a new survey is any indication, Republicans could end up sacrificing seats in the Senate if they refuse to allow a vote on President Barack Obama's nominee until after the elections in November.

A new CBS News poll out this morning finds that Donald Trump continues to dominate among Republican voters nationally: He’s backed by 35 percent; Ted Cruz has 18 percent; and Marco-Mentum has 12 percent. There was a great deal of excitement about yesterday’s NBC poll finding Trump had slipped behind Cruz, but that now looks like it may have been an outlier.

President Barack Obama on Thursday announced a historic visit to Cuba next month, speeding up the thaw in relations between the two Cold War former foes but igniting opposition from Republicans at home. In the first U.S. presidential trip to the Caribbean nation in nearly 90 years, Obama will meet with Cuban President Raul Castro, entrepreneurs, and "Cubans from different walks of life" during the trip on March 21 and 22, the White House said.

Concerted Republican opposition to considering President Barack Obama's pick for the Supreme Court showed early signs of splintering on Wednesday as a handful of influential senators opened the door to a possible confirmation hearing. One Republican even suggested the president should nominate a candidate from his state. Texas Sen. John Cornyn, the No. 2 Republican in the Senate, did not rule out a committee hearing on Obama's forthcoming nominee to replace the late Justice Antonin Scalia. And Sen. Dean Heller said chances of Senate approval were slim, but added that Obama should "use this opportunity to put the will of the people ahead of advancing a liberal agenda" on the high court.

Thirty-three minutes after the San Antonio Express-News reported the death of Antonin Scalia, I emailed several conservative consultants involved in past Supreme Court fights: “Can Obama get a replacement confirmed?” The first reply came nine minutes later: “Absolutely not,” the GOP operative replied. “We won’t let them vote.”